Why the Tory rebels are a long-term problem for Boris Johnson

Even if ministers succeed in passing the Internal Market Bill, the risk of future rebellions may only increase. 

David Cameron has become the latest high-profile Conservative, and the fifth former prime minister, to express their disquiet at the government's plan to break international law with the Internal Market Bill. But the more important high-profile critic – because he still has a vote in the House of Commons – is Geoffrey Cox, Boris Johnson's first attorney general, who has written for the Times that he cannot support the Bill because of its implications for international law.

Tonight's vote on the second reading of the IMB is likely to pass opposed only by a committed core of rebels, whether they do so through voting against it or via abstention. The big vote is next week – on Bob Neill's amendment to prevent any Secretary of State using the Internal Market Bill's law-breaking provisions without a further parliamentary vote – and the big risk to the government is the gradual ebbing of support between now and then. 

Cameron's criticism – that he has "misgivings" about the plans, but the most important thing is for the country to get a EU-UK trade agreement – may be more of a help than a hindrance to the government, in that it contains a ready-made excuse for any Conservative MP who thinks they ought to rebel, but is looking for a reason not to (this is not a small group).

The problem is that many MPs already feel that, because they have been vocal about Dom Cummings' lockdown breach, or because they have been sacked and told in blunt terms that Johnson sees no future for them, that they might as well vote with their consciences on this and any other issue. That's not a good position for a government to be in, this early in the parliament – particularly not a government which still harbours pretensions of delivering a radical legislative agenda. 

There are two problems with the government's approach. The first, obviously, is that it is countenancing breaking international law and increasing the chances of a no-deal Brexit. But the long-term problem that will place hard limits on the government's ability to get its business done is that, whether the government emerges from the coming weeks undefeated or not, the winnowing away of its majority will continue.